The present invention relates generally to electronic circuits such as integrated circuits, and more particularly to integrated RF circuits.
Signal switching, phase shifting, and polarization control are commonly needed in RF circuits. For example, phased array antenna systems may select which antennas are active and the phase delay associated with each active antenna and the type of polarization used in signal transmission and reception. While a number of techniques to achieve signal switching, phase shifting and polarization control in optical systems exist, these techniques are not amenable at RF and mmWave frequencies. At mmWave frequencies, electronically controlled signal switching, phase shifting, and polarization control has typically required separate function-specific circuits and components including phase shifters, switches, and variable gain control/variable attenuators that operate in the analog domain. However, the large number of circuit components used to achieve signal switching, phase shifting and polarization control consume a large chip area and degrade signal quality. Moreover, despite the large area and signal degradation introduced by such systems, these systems provide only coarse polarization control, by selecting from a few fixed polarization modes. Mechanical control of polarization is also possible but tends to be extremely slow and cumbersome.